Floating gardens are known, for example at the Epcot Center, Disney World, in Florida.
We have previously invented a floating garden structure for floating individually potted plants on the surface of a body of water such as a pond. The structure had a floating foam base with multiple through-bores from the top surface to the bottom surface, and potted plants were secured therein with a netting material so that their roots could grow through into the water. The upper and outer side surfaces of the structure were decorated with synthetic furnace filter material.
Problems with our earlier floating garden structure included a lack of durability and natural appearance in the outer covering; a tendency for the potted plant soil in the bores to be over-moist or flooded; and a tendency for the netting material to be difficult to install, to interfere with the potting of the plants in the bores, and to become detached from the bores over time.
Another problem with our earlier floating garden was that by riding high enough in the water to reduce the tendency of the potting soil in the bores to become flooded, turtles and other amphibians were unable to climb onto the structure.